The present invention relates to a method of fabricating an electrode plate for an ozone generator, and more particularly to such an electrode plate made by semiconductor micromachining technique.
Conventionally ultraviolet activating method and electric discharge method are commonly used to generate ozone. Ozone is generally formed by the action of oxygen atoms on oxygen molecules. The method of generating ozone by electric discharge is to split the oxygen molecules into oxygen atoms with corona discharge. According to the principle of electric discharge, the density of discharge current has great concern with the intensity of electric field at the surface of cathode electrode, i.e., the higher the intensity of electrode field, the higher the density of discharge current. The intensity of electric field is determined subject to the space between the cathode electrode and the anode electrode, i.e., the smaller the space, the higher the intensity of electric field. Further, the intensity of electric field is also determined subject to the surface geometric configuration of the cathode electrode. The intensity of electric field is higher at a sharper tip or edge, and it is lower at a flat surface. The value of discharge current is obtained from multiplying the density of discharge current by discharge area. Under a constant voltage, the discharge power becomes higher when the discharge current is raised, and relatively higher concentration of ozone can be produced. Therefore, an ideal ozone generator has a small discharge space between the cathode electrode and anode electrode, and the radius of curvature of the tip or edge of the discharge portions thereof is small.
Regular ozone generators are commonly made by conventional mechanical machinery. Exemplars are disclosed in U.S. Pat. No. 4,882,129, entitled "OZONE GENERATOR CELL", and U.S. Pat. No. 4,992,246, entitled "OZONIZER". The former teaches the installation of a thin ceramic sheet sandwiched between a perforated metallic sheet serving as cathode electrode and a water-cooled aluminum base. Dry air or oxygen is passed over the electrode surface and a high-voltage, high-frequency electric field is applied between the electrode and the base for a corona discharge. The later teaches the installation of a first electrode comprising blades, a second electrode comprising a casing, enabling the blades and the casing to form a blower. This arrangement makes it unnecessary to provide an apparatus for causing a corona discharge, and a blower for supplying oxygen to the discharge space and taking out the respectively generated ozone.
According to the aforesaid structures, the discharge space and the radius of the discharge tips (discharge portions) cannot be minimized thereby. Therefore, in order to generate the ozone, the applied voltage must be very high. However, the high applied voltage will consume more energy and tend to incur danger.
Further, according to the principle of discharge, the density of discharge current has a great concern with the intensity of electric field at the surface of the discharge portion on the cathode electrode, i.e., the higher the intensity of electric field is, the higher the density of discharge current will be, and the intensity of electric field is directly proportional to the discharge space between the cathode electrode and the anode electrode, i.e., the smaller the discharge space is, the higher the intensity of the electric field will be. In addition, the surface geometric configuration of the cathode electrode also concerns the intensity of electric field as indicated above.